Defending champion Manalapan, No. 3 in The Star-Ledger Top 20, was awarded the top seed last night for the Monmouth County Tournament, which commences this week with two preliminary-round games and first-round action on Saturday.The quarterfinals will be played on May 14 with a semifinal doubleheader slated for May 17 at FirstEnergy Park in Lakewood, which will also host the championship on a date to be determined.MONMOUTH COUNTY TOURNAMENT17-Rumson at 16-Colts Neck, winner at 1-Manalapan; 9-Christian Brothers at 8-Holmdel; 12-Mater Dei at 5-Red Bank Catholic; 13-Middletown North at 4-Ocean Twp.; 14-Freehold Twp. at 3-St. Rose; 11-Monmouth Reg. at 6-St. John Vianney; 10-Middletown South at 7-Red Bank; 18-Howell at 15-Freehold Borough, winner at 2-Wall.